Chevron firefighters may have gouged pipe

The pipe that fed a huge fire at Chevron’s Richmond oil refinery in August appears to have been punctured from the outside, possibly by company firefighters trying to get at a small leak before the blaze ignited, investigators said Thursday.

The 40-year-old pipe had already been weakened by the heavy sulfur content of the crude oil being pumped through it, according to a draft metallurgical report on the fire that was prepared for federal and state investigators.

The pipe developed a small hole the afternoon of Aug. 6 that mushroomed into a larger leak and then a fire that destroyed part of the refinery and sent a cloud of gas and smoke thousands of feet into the air. No one was seriously hurt in the fire, but 15,000 people sought hospital treatment for respiratory and other problems because of the smoke.

The metallurgical report shows the expected evidence of corrosion that led to the pipe bursting, according to two officials of the U.S. Chemical Safety Board, the lead federal agency in the probe.

But separately, the investigation has also turned up something unexpected, they said: Photos of the inside of the line show that at the point where the pipe failed, it appears to have been punctured from the outside.

Firefighters’ role?

Investigators are trying to determine whether Chevron firefighters responding to the first report of a small leak accidentally damaged the line as they tore away insulation.

“One theory we are exploring is that emergency response activities inadvertently accelerated the rate of the leak,” said Daniel Horowitz, managing director of the Chemical Safety Board. “We are comparing possible tool marks on the pipe with tools recovered from the incident.”

One tool that may have inflicted the apparent damage is a Halligan bar, which has a hook-like implement with a sharp end. Firefighters are commonly equipped with the device to help them gain entry into burning buildings.

Don Holmstrom, the Chemical Safety Board’s lead investigator looking into the fire, said the blaze might well have happened even without the apparent puncture, but that the external damage could have been “an aggravating factor.”

Investigators have not determined what sparked the blaze, but have raised questions about Chevron’s decision to continue to run crude oil through the pipe even as workers responded to the initial, small leak.

“Regardless of the exact sequence of the events, this incident emphasizes the importance of effective decision-making in shutting down the unit promptly in case of a leak of this type,” Horowitz said.

A Chevron spokesman issued a statement saying: “This is part of the ongoing investigation into the Aug. 6 fire at the refinery. We have been working closely and cooperatively with the investigating agencies, as well as conducting our own investigation. It is premature to comment on specific details until the investigations are complete.”

A hydrocarbon vapor cloud spewed from the pipe soon after Chevron workers removed the insulation from the leaking line, federal investigators said. A resulting flash fire was quickly extinguished, but within minutes another blaze – fed by fumes escaping from a gash of several inches on the 8-inch-diameter pipe – ignited and consumed part of the refinery.

Corroded pipe

The draft metallurgical report, prepared by Anamet Inc. of Hayward, has been given to Chevron, investigating agencies and the union representing refinery workers. It might be released publicly after the parties’ comments are included, investigators say.

The report affirms Chevron’s theory that high-temperature, sulfur-laden crude caused the thinning and initial leak in the pipe, Holmstrom and Horowitz confirmed.

The pipe was made out of carbon steel, which Chevron has concluded was low in silicon and susceptible to corrosion from sulfur-heavy crude. In its effort to get the refinery fully back online, Chevron is installing pipe made out of a material called 9-Chrome, an alloy that contains more corrosion-fighting chromium.

Richmond officials had delayed issuing permits while two consultants evaluated whether Chevron’s choice, 9-Chrome, was the best available technology. Chevron’s own internal documents said stainless steel is more corrosion-resistant than 9-Chrome, but company officials told city officials that stainless steel is vulnerable to unpredictable cracking.

After Chevron threatened to lay off more than 600 workers if it didn’t get city permits for the reconstruction, Richmond gave the go-ahead late last month – although Mayor Gayle McLaughlin said the affair left her frustrated.

“Had we had all the information first, that is always the better way to approach dilemmas and uncertainty,” McLaughlin said. “Staff said they had an obligation to go forward – that it was an administrative decision and they made it.”

Shauna Lawhorne, with Chemical Safety Board public affairs, displays photos on Monday, August 20, 2012 in Richmond, Calif., of the vapor cloud at the Chevron refinery that exploded on Aug. 6. Photo: Carlos Avila Gonzalez, The Chronicle / SF less

Shauna Lawhorne, with Chemical Safety Board public affairs, displays photos on Monday, August 20, 2012 in Richmond, Calif., of the vapor cloud at the Chevron refinery that exploded on Aug. 6. Photo: Carlos ... more

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Firefighting crews continue to pour water onto a unit after a fire at a Chevron refinery on Tuesday, Aug. 7, 2012 in Richmond, Calif. The fire, which sent plumes of black smoke over the San Francisco Bay area, erupted Monday evening in the massive Chevron refinery about 10 miles (16 kilometers) northeast of San Francisco. It was out early Tuesday. (AP Photo/The Contra Costa Times, Aric Crabb) less

Firefighting crews continue to pour water onto a unit after a fire at a Chevron refinery on Tuesday, Aug. 7, 2012 in Richmond, Calif. The fire, which sent plumes of black smoke over the San Francisco Bay area, ... more

Photo: AP

Image 6 of 42

Firefighting crews continue to pour water onto a unit after a fire at a Chevron refinery on Tuesday, Aug. 7, 2012 in Richmond, Calif. The fire, which sent plumes of black smoke over the San Francisco Bay area, erupted Monday evening in the massive Chevron refinery about 10 miles (16 kilometers) northeast of San Francisco. It was out early Tuesday. (AP Photo/The Contra Costa Times, Aric Crabb) less

Firefighting crews continue to pour water onto a unit after a fire at a Chevron refinery on Tuesday, Aug. 7, 2012 in Richmond, Calif. The fire, which sent plumes of black smoke over the San Francisco Bay area, ... more

Photo: AP

Image 7 of 42

Firefighting crews continue to pour water onto a unit after a fire at a Chevron refinery on Tuesday, Aug. 7, 2012 in Richmond, Calif. The fire, which sent plumes of black smoke over the San Francisco Bay area, erupted Monday evening in the massive Chevron refinery about 10 miles (16 kilometers) northeast of San Francisco. It was out early Tuesday. (AP Photo/The Contra Costa Times, Aric Crabb) less

Firefighting crews continue to pour water onto a unit after a fire at a Chevron refinery on Tuesday, Aug. 7, 2012 in Richmond, Calif. The fire, which sent plumes of black smoke over the San Francisco Bay area, ... more

Photo: AP

Image 8 of 42

White smoke rises from the Chevron refinery during a controlled burn on Tuesday, Aug. 7, 2012, the morning after Monday's toxic fire in Richmond, Calif. An investigation into what caused the fire is ongoing. Heather Kulp, Chevron spokesperson, said the fire was caused by a vapor leak. (AP Photo/The Contra Costa Times, Laura A. Oda) less

White smoke rises from the Chevron refinery during a controlled burn on Tuesday, Aug. 7, 2012, the morning after Monday's toxic fire in Richmond, Calif. An investigation into what caused the fire is ongoing. ... more

Photo: AP

Image 9 of 42

White smoke rises from the Chevron refinery during a controlled burn on Tuesday, Aug. 7, 2012, the morning after Monday's toxic fire in Richmond, Calif. An investigation into what caused the fire is ongoing. Heather Kulp, Chevron spokesperson, said the fire was caused by a vapor leak. (AP Photo/The Contra Costa Times, Laura A. Oda) less

White smoke rises from the Chevron refinery during a controlled burn on Tuesday, Aug. 7, 2012, the morning after Monday's toxic fire in Richmond, Calif. An investigation into what caused the fire is ongoing. ... more

Photo: AP

Image 10 of 42

In this undated photo released by the U.S. Chemical Safety Board, structural damage is shown after the Chevron refinery fire in Richmond, Calif. Structural engineers have deemed the site of a Chevron refinery fire in the San Francisco Bay area hazardous for human entry after looking at the failed pipe that leaked and sent a towering plume of black smoke into the sky. Federal and state investigators are discussing plans for how to make the Richmond site safe so the faulty pipe can be removed for testing. (AP Photo/U.S. Chemical Safety Board, handout) less

In this undated photo released by the U.S. Chemical Safety Board, structural damage is shown after the Chevron refinery fire in Richmond, Calif. Structural engineers have deemed the site of a Chevron refinery ... more

Photo: AP

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In this undated photo released by the U.S. Chemical Safety Board, a pipe is shown after the Chevron refinery fire in Richmond, Calif. Structural engineers have deemed the site of a Chevron refinery fire in the San Francisco Bay area hazardous for human entry after looking at the failed pipe that leaked and sent a towering plume of black smoke into the sky. Federal and state investigators are discussing plans for how to make the Richmond site safe so the faulty pipe can be removed for testing. (AP Photo/U.S. Chemical Safety Board) less

In this undated photo released by the U.S. Chemical Safety Board, a pipe is shown after the Chevron refinery fire in Richmond, Calif. Structural engineers have deemed the site of a Chevron refinery fire in the ... more

Photo: AP

Image 12 of 42

In this undated photo released by the U.S. Chemical Safety Board, structural damage is shown after the Chevron refinery fire in Richmond, Calif. Structural engineers have deemed the site of a Chevron refinery fire in the San Francisco Bay area hazardous for human entry after looking at the failed pipe that leaked and sent a towering plume of black smoke into the sky. Federal and state investigators are discussing plans for how to make the Richmond site safe so the faulty pipe can be removed for testing. (AP Photo/U.S. Chemical Safety Board, handout) less

In this undated photo released by the U.S. Chemical Safety Board, structural damage is shown after the Chevron refinery fire in Richmond, Calif. Structural engineers have deemed the site of a Chevron refinery ... more

Photo: AP

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Dr. Rafael Moure-Eraso, Chairman of the Chemical Safety Board, addresses the press as they released photos on Monday, August 20, 2012 in Richmond, Calif., of the vapor cloud at the Chevron refinery that exploded on Aug. 6. Photo: Carlos Avila Gonzalez, The Chronicle / SF less

Dr. Rafael Moure-Eraso, Chairman of the Chemical Safety Board, addresses the press as they released photos on Monday, August 20, 2012 in Richmond, Calif., of the vapor cloud at the Chevron refinery that ... more

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Fire at the Chevron Refinery in Richmond as seen from Tiburon, Calif. on Monday August 6th, 2012. Photo: John Storey, Special To The Chronicle / SF

Fire at the Chevron Refinery in Richmond as seen from Tiburon, Calif. on Monday August 6th, 2012. Photo: John Storey, Special To The Chronicle / SF

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Flames and smoke shoot up from the Chevron refinery, a fixture in Richmond for more than a century. Photo: John Sebastian Russo, Special To The Chronicle / SF

Flames and smoke shoot up from the Chevron refinery, a fixture in Richmond for more than a century. Photo: John Sebastian Russo, Special To The Chronicle / SF

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Smoke from the Chevron refinery fills the sky above Richmond after a series of explosions beginning around 6:15 p.m. No one was killed, Chevron said. Photo: Lance Iversen, The Chronicle / SF

Smoke from the Chevron refinery fills the sky above Richmond after a series of explosions beginning around 6:15 p.m. No one was killed, Chevron said. Photo: Lance Iversen, The Chronicle / SF

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Chevron oil refinery, Richmond / SF

Chevron oil refinery, Richmond / SF

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Crews fight the fire at the Chevron refinery. The fire reportedly started at the No. 4 Crude Unit. Photo: Lance Iversen, The Chronicle / SF

Crews fight the fire at the Chevron refinery. The fire reportedly started at the No. 4 Crude Unit. Photo: Lance Iversen, The Chronicle / SF

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Smoke from the Chevron refinery fills the sky above Richmond after a series of explosions beginning around 6:15 p.m. No one was killed, Chevron said. Photo: Lance Iversen, The Chronicle / SF

Smoke from the Chevron refinery fills the sky above Richmond after a series of explosions beginning around 6:15 p.m. No one was killed, Chevron said. Photo: Lance Iversen, The Chronicle / SF

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Smoke from the Chevron refinery fills the sky above Richmond after a series of explosions beginning around 6:15 p.m. No one was killed, Chevron said. Photo: Lance Iversen, The Chronicle / SF

Smoke from the Chevron refinery fills the sky above Richmond after a series of explosions beginning around 6:15 p.m. No one was killed, Chevron said. Photo: Lance Iversen, The Chronicle / SF

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Fire at the Chevron Refinery in Richmond as seen from Tiburon, Calif. on Monday August 6th, 2012. Photo: John Storey, Special To The Chronicle / SF

Fire at the Chevron Refinery in Richmond as seen from Tiburon, Calif. on Monday August 6th, 2012. Photo: John Storey, Special To The Chronicle / SF

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Plumes of smoke emanate from the Chevron oil refinery on Monday, August 6, 2012 in Richmond, Calif. Photo: Beck Diefenbach, Special To The Chronicle / SF

Plumes of smoke emanate from the Chevron oil refinery on Monday, August 6, 2012 in Richmond, Calif. Photo: Beck Diefenbach, Special To The Chronicle / SF

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A fire in is seen at the Chevron Refinery in Richmond, Calif. Photo: Courtesy Tom Butt / SF

A fire in is seen at the Chevron Refinery in Richmond, Calif. Photo: Courtesy Tom Butt / SF

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A fire in is seen at the Chevron Refinery in Richmond, Calif. Photo: Courtesy Tom Butt / SF

A fire in is seen at the Chevron Refinery in Richmond, Calif. Photo: Courtesy Tom Butt / SF

Image 25 of 42

Smoke from the Chevron refinery fills the sky above Richmond after a series of explosions beginning around 6:15 p.m. No one was killed, Chevron said. Photo: Lance Iversen, The Chronicle / SF

Smoke from the Chevron refinery fills the sky above Richmond after a series of explosions beginning around 6:15 p.m. No one was killed, Chevron said. Photo: Lance Iversen, The Chronicle / SF

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Smoke from the fire at the Chevron refinery in Richmond is seen from Benicia, Calif., on August 6, 2012. Photo: Courtesy Nate Kane / SF

Smoke from the fire at the Chevron refinery in Richmond is seen from Benicia, Calif., on August 6, 2012. Photo: Courtesy Nate Kane / SF

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Nigel Hearne, manager of Chevron's Richmond refinery, says the fire was started when a diesel leak ignited. Photo: Stephen Lam, Special To The Chronicle / SF

Nigel Hearne, manager of Chevron's Richmond refinery, says the fire was started when a diesel leak ignited. Photo: Stephen Lam, Special To The Chronicle / SF

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Smoke and fire from the Chevron Oil Refinery fire as seen in Richmond, Calif. on Monday, Aug. 6, 2012. Photo: Stephen Lam, Special To The Chronicle / SF

Smoke and fire from the Chevron Oil Refinery fire as seen in Richmond, Calif. on Monday, Aug. 6, 2012. Photo: Stephen Lam, Special To The Chronicle / SF

John Smith, of Richmond, watches the Chevron Oil Refinery fire from a distance through a fence on Castro Road in Richmond, Calif. on Monday, Aug. 6, 2012. Photo: Stephen Lam, Special To The Chronicle / SF

John Smith, of Richmond, watches the Chevron Oil Refinery fire from a distance through a fence on Castro Road in Richmond, Calif. on Monday, Aug. 6, 2012. Photo: Stephen Lam, Special To The Chronicle / SF

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A group of teenagers watches smoke and fire from the Chevron Oil Refinery fire in Richmond, Calif. on Monday, Aug. 6, 2012. Photo: Stephen Lam, Special To The Chronicle / SF

A group of teenagers watches smoke and fire from the Chevron Oil Refinery fire in Richmond, Calif. on Monday, Aug. 6, 2012. Photo: Stephen Lam, Special To The Chronicle / SF

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Smoke and fire from the Chevron Oil Refinery fire as seen in Richmond, Calif. on Monday, Aug. 6, 2012. Photo: Stephen Lam, Special To The Chronicle / SF

Smoke and fire from the Chevron Oil Refinery fire as seen in Richmond, Calif. on Monday, Aug. 6, 2012. Photo: Stephen Lam, Special To The Chronicle / SF

Image 35 of 42

Flames and smoke shoot up from the Chevron refinery, a fixture in Richmond for more than a century. Photo: John Sebastian Russo, Special To The Chronicle / SF

Flames and smoke shoot up from the Chevron refinery, a fixture in Richmond for more than a century. Photo: John Sebastian Russo, Special To The Chronicle / SF

Image 36 of 42

Smoke bellows from a fire at the Chevron refinery following an explosion at 6:30 on Monday, August 6, 2012 in Richmond, Calif.
Photo: John Sebastian Russo, Special To The Chronicle / SF

Smoke bellows from a fire at the Chevron refinery following an explosion at 6:30 on Monday, August 6, 2012 in Richmond, Calif.
Photo: John Sebastian Russo, Special To The Chronicle / SF

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Smoke bellows from a fire at the Chevron refinery following an explosion at 6:30 on Monday, August 6, 2012 in Richmond, Calif.
Photo: John Sebastian Russo, Special To The Chronicle / SF

Smoke bellows from a fire at the Chevron refinery following an explosion at 6:30 on Monday, August 6, 2012 in Richmond, Calif.
Photo: John Sebastian Russo, Special To The Chronicle / SF

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Marce Gutierrez, of Hercules, watches of plumes of smoke emanate from the Chevron oil refinery on Monday, August 6, 2012 in Richmond, Calif. "I'm just trying to figure out if we need to leave," Gutierrez said. Photo: Beck Diefenbach, Special To The Chronicle / SF less

Marce Gutierrez, of Hercules, watches of plumes of smoke emanate from the Chevron oil refinery on Monday, August 6, 2012 in Richmond, Calif. "I'm just trying to figure out if we need to leave," Gutierrez said. ... more

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Andres Locky takes a photo of himself in front of plumes of smoke emanating from the Chevron oil refinery on Monday, August 6, 2012 in Richmond, Calif. Photo: Beck Diefenbach, Special To The Chronicle / SF

Andres Locky takes a photo of himself in front of plumes of smoke emanating from the Chevron oil refinery on Monday, August 6, 2012 in Richmond, Calif. Photo: Beck Diefenbach, Special To The Chronicle / SF

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Elizabeth Fein, of El Cerrito, takes a photo of plumes of smoke emanating from the Chevron oil refinery on Monday, August 6, 2012 in Richmond, Calif. Photo: Beck Diefenbach, Special To The Chronicle / SF

Elizabeth Fein, of El Cerrito, takes a photo of plumes of smoke emanating from the Chevron oil refinery on Monday, August 6, 2012 in Richmond, Calif. Photo: Beck Diefenbach, Special To The Chronicle / SF

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Fire at the Chevron Refinery in Richmond as seen from the Berkeley Marina on Monday August 6th, 2012. Photo: Will Kane, San Francisco Chronicle / SF

Fire at the Chevron Refinery in Richmond as seen from the Berkeley Marina on Monday August 6th, 2012. Photo: Will Kane, San Francisco Chronicle / SF